WATERTOWN — Mother Nature needs to be tamed for raspberries to thrive in the north country.
And for Gail C. Millard, a high tunnel with temperature-controlled curtains built in the summer of 2012 has gotten that job done at Little m Farm off County Road 64 in the town of Watertown. The 66-year-old, who invested about $15,000 to build the tunnel, said he expects the harvest of its three rows of raspberry canes to be excellent this fall.
Since July, he has picked enough raspberries to fill 15 to 50 half-pints each week. Half-pints are sold for $3 apiece at his store, which also offers an array of fresh vegetables and fruits grown on the farm. Most of the raspberries are sold to members of a Burrville-based community-supported agriculture program called Miracles by the Acre.
Years of planning the tunnel have finally paid off for Mr. Millard, who said it has safeguarded the plants from the elements and tempered hot summer weather to create ideal growing conditions.
“We’re not harvesting a lot yet, but it keeps up with the product I’m selling right now,” said Mr. Millard, who operates the business with his wife, Ann M. “There was a steep learning curve, and it took a lot of work to do this.”
Mr. Millard said he spent several years researching how to build the high tunnel before successfully applying for a grant from the U.S. Department of Agriculture of about $5,300 in 2011. Only one row of raspberry canes was available to harvest last summer, he said, because other rows were planted too late in the season. This summer, by contrast, canes have grown up to 9 feet tall. Three varieties of raspberries are grown in the tunnel: Crimson Night, Double Gold and Joan-J. Joan-J raspberries typically begin to bloom in July, while the other two varieties start blooming in September.
Mr. Millard gave the Times a tour of the 2,500-square-foot tunnel on Wednesday, which he bought from New Hampshire-based Rimol Greenhouse systems. He explained how the tunnel’s sturdy design is built to weather north country winters. Its canopy’s double-layer of air-tight plastic, which is supported by a network of trusses, effectively insulated the plants during the winter months, he said.
“Most high tunnels only have one layer of plastic that you would take off in the fall and put on in the spring,” he said. “But I decided that wouldn’t work here because the wind and snow can be wicked. The plastic stays tight when we get snow, and it slides right off the top.”
Its automated roll-up curtains are powered by gearbox motors attached to roll bars on both sides, which are 96 feet long. The automated curtains are programed so they’ll close when temperatures drop during nights in the fall to help retain heat. When the temperatures climb during the day, curtains may be programmed to open the curtains up to keep sweltering heat at bay. Four large ceiling-mounted fans also keep air circulating.
“During the day, it is designed to start rolling up from 69 to 83 degrees,” he said. “What you’re trying to do is to control the temperature to avoid extremes. And if I want, I can hit a button to make it go down and up automatically.”
The tunnel’s irrigation system includes drip lines that run underneath each row of canes to keep the soil hydrated, Mr. Millard said. Well water is pumped from a 300-gallon tank into the tunnel at 40 pounds per square inch. That water goes through a pressure regulator that reduces the flow to about 10 pounds per square inch before it enters drip lines. Plants are watered about every other day during the summer, depending on the weather.
“We use 150 gallons about every other day,” he said.
Mr. Millard, meanwhile, continues to make plans to improve the tunnel next year. He plans to build a gutter system, for example, to collect rain water that flows off into a large holding tank. Installing ground-mounted solar panels to power the tunnel also will be explored, he said, and the irrigation system could be upgraded to become semi-automated.
“Tensiometers would measure moisture in the soil and electronically open the valve in your system to irrigate plants,” he said, adding that the technology would make his job easier. “I want to make the tunnel as self-sustaining as possible.”
Video featuring the high tunnel can be viewed at http://wdt.me/high-tunnel.